System and method for size estimation of in-vivo objects

ABSTRACT

A system, method and virtual tool for size estimation of in-vivo objects includes receiving and displaying a two-dimensional image of in-vivo objects obtained by in-vivo imaging device; receiving indication of a selected area representing a point of interest from the user via a user input device; estimating depth of a plurality of image pixels around the selected area; calculating three-dimensional coordinates representation of the plurality of image points, based on the estimated depths; casting a virtual tool of a known size onto the three-dimensional representation; and projecting the virtual tool onto the two-dimensional image to create a cursor having a two-dimensional shape on the displayed image.

FIELD OF THE INVENTION

The present invention relates to the field of estimating a geometricalparameter of objects in an image. More specifically, the presentinvention relates to estimating or determining a size of objects in animage. In particular, the present invention relates to images obtainedby an in-vivo device, and to a virtual tool for estimating size ofin-vivo objects, regions or tissues.

BACKGROUND OF THE INVENTION

Known devices may be helpful in providing in-vivo sensing, for example,using imaging techniques, systems and/or methods. One of the uses forsuch devices may be in detecting and/or identifying objects or tissuesthat may indicate in-vivo pathologies. Autonomous in-vivo sensingdevices, e.g., swallowable or ingestible capsules or other devices maymove through a body lumen, sensing, monitoring or otherwise obtainingdata as they move along body lumens. Such autonomous in-vivo sensingdevices may include, for example, an imager for obtaining images of abody cavity or lumen, such as the gastrointestinal (GI) tract. Suchautonomous in-vivo sensing devices may include an optical system, alight source, a controller and optionally a transmitter and an antenna.Some of these devices use a wireless connection to transmit image data.

Different methods for estimating the size of objects imaged in a bodylumen exist. For example, an in-vivo device may emit a laser beam andmay further acquire an image of a spot on a tissue created by such beamas well as surrounding tissues or region. A distance of the spot fromthe in-vivo device may be calculated, e.g., based on the location of thespot in an image. Various parameters, coefficients or other informationrelated to a color or other optical aspects of nearby tissue (that maybe assumed to be in the same and known distance of the laser beam spot)may be calculated and applied to other regions, objects or tissues inthe image in order to calculate a distance of such other regions,objects or tissues from the in-vivo device.

When using an endoscope for in-vivo examination, the endoscope mayinclude an actual forceps (endoscopic forceps) which may enable aprofessional to estimate size of in-vivo objects by opening the forceps'arms to the size of the in-vivo objects.

SUMMARY OF THE INVENTION

Embodiments of the present invention may provide a system and method forsize estimation of in-vivo objects, the method including displaying atwo-dimensional image of in-vivo objects obtained by in-vivo imagingdevice, said image comprising image pixels, receiving indication of aselected area representing a point of interest from the user, estimatingthe depth, e.g, the distance of an object from the imaging device, andcalculating a three-dimensional coordinates representation of theplurality of image pixels, based on the estimated depths.

Additionally, a method according to embodiments of the present inventionincludes projecting or casting a virtual tool of a known size onto thethree-dimensional representation (e.g., adding the tool to therepresentation) to determine ending points of the tool. The projectingor casting may include and/or may be performed in order to determineending points of multiple lengths of the virtual tool. The projecting orcasting may include creating a virtual tool having an origin point andmultiple extensions extending from the origin point or lengths from theorigin point in multiple directions and an origin point from which theextensions extend, and positioning ending points of the multipleextensions or lengths on points defined by three coordinates inthree-dimensional space, on the three-dimensional representation,wherein each of the ending points is positioned at a same pre-determinedabsolute distance in millimeters from the point of interest in thethree-dimensional representation. The positioning may include checkingthe absolute distance from the origin point to multiple points on thethree-dimensional representation of the tissue along a certaindirection, and if, for a certain point, the absolute distance equals thepre-determined distance, determining the certain point as the positionof an ending point.

Additionally, a method according to embodiments of the present inventionincludes adding or projecting the virtual tool onto the two-dimensionalimage to create a cursor or other on-screen indication tool having atwo-dimensional shape on the displayed image, the cursor having multipledimensions in different directions, the dimensions end at the determinedending points projected on the two-dimensional image. The projecting mayinclude creating a two-dimensional cursor having multiple projecteddimensions in multiple directions, the dimensions end at the determinedending points projected on the two-dimensional image, wherein theprojected dimensions are the distances on the two-dimensional image fromthe ending points, projected on the displayed image, to the point ofinterest, selected or marked on the displayed image.

Additionally, the cursor according to embodiments of the presentinvention is movable over the displayed image, while the projecteddimensions are changeable dynamically according to the distances on thetwo-dimensional image from the ending points, projected on the displayedimage, to the point of interest, selected or marked on the displayedimage, wherein the point of interest is changed as the cursor is movedor repositioned over the displayed image.

A system for size estimation of in-vivo objects according to embodimentsof the present invention may include a workstation comprising a memoryand a processor, the memory to store an image captured by an in-vivoimaging device. The processor may be configured to: display atwo-dimensional image of in-vivo objects obtained by in-vivo imagingdevice; receive indication of a selected area representing a point ofinterest from the user via a user input device; calculate athree-dimensional coordinates representation of the plurality of imagepixels, based on the estimated depths; cast a virtual tool of a knownsize onto the three-dimensional representation to determine endingpoints of the tool; and project the virtual tool onto thetwo-dimensional image to create a cursor having a two-dimensional shapeon the displayed image, the cursor having multiple dimensions indifferent directions, the dimensions end at the determined ending pointsprojected on the two-dimensional image.

Further, the processor may be configured to: create a virtual toolhaving an origin point and multiple extensions extending from the originpoint in multiple directions or lengths from the origin point inmultiple directions that end at said ending points in the multipledirections; and position ending points of the multiple extensions orlengths on points defined by three coordinates in three-dimensionalspace, on the three-dimensional representation, wherein each of theending points is positioned at a same pre-determined absolute distancefrom the point of interest in the three-dimensional representation.

Further, the processor may be configured to: check the absolute distancefrom the origin point to multiple points on the three-dimensionalrepresentation of the tissue along a certain direction; and if, for acertain point, the absolute distance equals the pre-determined distance,determine the certain point as the position of an ending point.

Further, the processor may be configured to create a two-dimensionalcursor having multiple projected dimensions in multiple directions,wherein the projected dimensions are the distances on thetwo-dimensional image from the ending points, projected on the displayedimage, to the point of interest, selected or marked on the displayedimage.

According to further embodiments of the present invention, a method forsize estimation of in-vivo objects includes creating a virtualmeasurement tool for size estimation of in-vivo objects, the toolcomprising an origin point on a point of interest on a displayedtwo-dimensional image, and multiple lengths from the origin point inmultiple directions in a three-dimensional representation of the imageof a tissue captured by said in-vivo imaging device, each length havingan ending point at a distal end of the length, positioned on a point inthe three-dimensional representation of the image, wherein the endingpoints have the same absolute distance from the origin point in thethree-dimensional representation, and projecting the virtual measurementtool on said image, for creating a two-dimensional cursor havingmultiple projected dimensions in multiple directions, the projecteddimensions being the distances on the two-dimensional image from theending points, projected on the displayed image, to the point ofinterest, selected on the displayed image.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are illustrated by way of example and notlimitation in the figures of the accompanying drawings, in which likereference numerals indicate corresponding, analogous or similarelements, and in which:

FIG. 1 shows a schematic diagram of an in-vivo imaging device accordingto embodiments of the invention;

FIG. 2 shows a schematic illustration of an in-vivo imaging system,according to an embodiment of the present invention;

FIG. 3 is a schematic cross-sectional illustration of a virtual toolbeing cast on a cross-sectional illustration of a three-dimensionalpresentation of an imaged tissue, for example as may be calculated by adepth estimation model according to embodiments of the presentinvention;

FIGS. 4A, 4B and 4C which are schematic illustrations of a displayedimage, for example captured by an in-vivo device, and a virtualmeasurement tool displayed upon the image, according to embodiments ofthe present invention; and

FIG. 5 is a flowchart illustrating a method for size estimation ofin-vivo objects according to embodiments of the present invention.

It will be appreciated that for simplicity and clarity of illustration,elements shown in the figures have not necessarily been drawn accuratelyor to scale. For example, the dimensions of some of the elements may beexaggerated relative to other elements for clarity, or several physicalcomponents may be included in one functional block or element. Further,where considered appropriate, reference numerals may be repeated amongthe figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Inother instances, well-known methods, procedures, and components,modules, units and/or circuits have not been described in detail so asnot to obscure the invention.

Although embodiments of the invention are not limited in this regard,discussions utilizing terms such as, for example, “processing,”“computing,” “calculating,” “determining,” “establishing”, “analyzing”,“checking”, or the like, may refer to operation(s) and/or process(es) ofa computer, a computing platform, a computing system, or otherelectronic computing device, that manipulate and/or transform datarepresented as physical (e.g., electronic) quantities within thecomputer's registers and/or memories into other data similarlyrepresented as physical quantities within the computer's registersand/or memories or other information storage medium that may storeinstructions to perform operations and/or processes.

Although embodiments of the invention are not limited in this regard,the terms “plurality” and “a plurality” as used herein may include, forexample, “multiple” or “two or more”. The terms “plurality” or “aplurality” may be used throughout the specification to describe two ormore components, devices, elements, units, parameters, or the like.Unless explicitly stated, the method embodiments described herein arenot constrained to a particular order or sequence. Additionally, some ofthe described method embodiments or elements thereof can occur or beperformed at the same point in time.

Embodiments of the system and method of the present invention may beused in conjunction with an imaging system or device capable ofobtaining images of in-vivo objects. More specifically, in someembodiments, any imaging device or system that may be installed in anin-vivo device as described herein may be used. However, it will beunderstood that embodiments of the invention are not limited by thetype, nature or other relevant aspects of the imaging system, device orunit used.

Some embodiments of the present invention are directed to a typicallyswallowable in-vivo device, such as an autonomous swallowable imagingdevice. Other embodiments need not be swallowable or autonomous, and mayhave other shapes or configurations. Devices according to embodiments ofthe present invention, including imaging, receiving, processing, storageand/or display units suitable for use with embodiments of the presentinvention, may be similar to embodiments described in U.S. Pat. No.7,009,634 and/or in U.S. Pat. No. 5,604,531, each of which are assignedto the common assignee of the present invention and each of which arehereby incorporated by reference in their entirety. Of course, devicesand systems as described herein may have other configurations and othersets of components.

According to one embodiment, an in-vivo imaging device may collect aseries of still images as it traverses the GI tract. The images may belater presented as, for example, a stream or sequence of images or amoving image of the traverse of the GI tract. An in-vivo imaging deviceor system may collect a large volume of data, as the in-vivo imagingdevice may take several hours to traverse the GI tract. The in-vivoimaging device may record images at a rate of, for example, four toforty images per second (other rates, such as two frames per second, maybe used). The in-vivo imaging device may have a fixed or variable framecapture and/or transmission rate. When the in-vivo imaging device has avariable or adaptive frame rate (AFR), the in-vivo imaging device mayswitch back and forth between frame rates, for example, based onparameters, such as an imaging device speed, estimated location,similarity between consecutive images, or other criteria. A total ofthousands of images, for example, 50,000 images, may be recorded. Theimage recordation rate, the frame capture rate, the total number ofimages captured, the total number of images selected if the moving imageis edited, and the view time of the moving image, may each be fixed orvaried.

The image data recorded and transmitted by the in-vivo imaging devicemay be digital color image data, although in alternate embodiments otherimage formats may be used. In one example, each frame of image data mayinclude 320 rows of 320 pixels each, each pixel including bytes forcolor and brightness, according to known methods. For example, in eachpixel, color may be represented by a mosaic of four sub-pixels, eachsub-pixel corresponding to primaries such as red, green, or blue (whereone primary is represented twice). The brightness of the overall pixelmay be recorded by a one byte (i.e., 0-255) brightness value. Accordingto one embodiment, images may be stored sequentially in a data processorstorage unit (for example, storage 630 in FIG. 2). The stored data mayinclude one or more pixel properties, including color, intensity andbrightness.

While information gathering, storage and processing are described to beperformed by certain units, the system and method of the presentinvention may be practiced with alternate configurations. For example,the components gathering image information need not be contained in animaging device, but may be contained in any other vehicle suitable fortraversing a lumen in a human body, such as an endoscope, stent,catheter, needle, etc. A data processor storage unit may store a seriesof images recorded by an in-vivo imaging device. The images the in-vivoimaging device records as it moves through a patient's GI tract may becombined consecutively to form a moving image stream or video.

An imaging parameter or imaging information as referred to herein may beany information related to or associated with an image. For example,imaging parameters, values or information may be associated with, andobtained from pixels in a digital image as known in the art.Accordingly, it will be understood that any information that may beassociated with pixels of a digital image or other imagingrepresentations, e.g., a hue, intensity, color, saturation and the likemay be obtained, analyzed and/or processed as described herein.Likewise, an image as referred to herein may typically (but notnecessarily) be a digital image or representation of a space or a sceneas captured by an imaging device. Embodiments of the invention may basea processing of an image on specific information, parameters or otheraspects of the imaging device, e.g., a relation of pixels to size may bedetermined using a known resolution parameter of the imaging device usedfor acquiring or digitizing an image. Accordingly, parameters related tothe imaging device may likewise be referred to herein as imagingparameters.

According to some embodiments, a distance from an imaging device and/ora size of an object may be determined or estimated by obtaining a tissuemodel designed to provide at least a mapping of at least one imagingparameter to at least one distance parameter, obtaining, by an imagingsystem, a digital image of the object, selecting at least one pixel inthe digital image, wherein such at least one pixel is associated withthe object, e.g., represents at least part of the object in the digitalimage and calculating, based on the tissue model and data associatedwith the pixel, a distance parameter related to a distance of the objectfrom the imaging system.

For example, given the distance of an object in an image (e.g., thedistance of the object from the imaging system at the time the image wasacquired), a relation of the number of pixels associated with the object(e.g., the number of pixels enclosed by an edge or border of the object)with the size of the object may be determined based on known parametersof the imaging system.

Reference is now made to FIG. 1, which shows a schematic diagram of anin-vivo imaging device 100 according to one embodiment of the presentinvention. As shown, in-vivo imaging device 100 may include an imagingsystem 110, a light source 120, a computing device 130, a receivertransmitter 140, a power source 150 (e.g., an internal battery or awireless receiving system) and a viewing window or dome 160. In someembodiments, in-vivo imaging device 100 may be, for example, aswallowable capsule capable of capturing images and/or obtain otherdata. More specifically, in-vivo device 100 may be configured, designedor otherwise enabled to independently obtain images and furtherconfigured to perform at least one of: processing, storing images andother information, communicating images to a remote computing orcommunication device and/or provide information, data or parametersrelated to obtained and/or processed images. For example, while inside abody of a human or other living creature, in-vivo device 100 may obtainimages of tissues, objects or its surroundings, store, processand/communicate such obtained images as well as possibly calculate,compute, determine and provide various indications, alarms, results ormeasurements.

In some embodiments, in-vivo device 100 may be in the shape of a capsuleas shown in FIG. 1, including for example a viewing window or dome 160.Viewing window 160 may be convex or substantially convex and smooth, andmay project outward from the main body and/or housing of device 110.Viewing window 160 may be designed to provide a suitable field of view(FOV) for imaging system 110 and/or to enable light from light source120 to reach objects outside device 110, e.g., object 170 as shown.Other shapes may be used, and the device need not be swallowable or acapsule. For example, device 100 may be implanted, inserted or otherwiselocated in any applicable location.

Imaging system 110 may be any suitable imaging system. For example,imaging system 110 may include any number of lenses or mirrors, supportassemblies that may be used to direct imaging system 110 at a specificdirection or angle and/or an embedded control module. Imaging system 110may comprise a complementary metal oxide semiconductor (CMOS) imagingcamera. As known in the art, a CMOS imager is typically an ultra-lowpower imager and is provided in chip scale packaging (CSP). Other typesof CMOS or other imagers may be used, e.g., a CCD imager. A 320×320pixel imager may be included in imaging system 110, e.g., one havingpixel size between 5 to 6 microns. According to some embodiments pixelsmay be each fitted with a micro lens.

Light source 120 may be any suitable light or energy source capable ofproducing, e.g., periodically or continually, light or other form ofenergy that may interact with objects outside device 100, e.g., object170 shown in FIG. 1. For example, light emitted periodically orcontinually by light source 120 may be reflected from such objects andcaptured by imaging system 110. For example, light source 120 may be aset of light emitting diodes (LEDs), organic LEDs (OLEDs), or othersuitable light sources, may provide light to illuminate objects thusenable acquiring images as known in the art. In other embodiments, otherforms of energy or types of light may be produced by light source 120,e.g., any form light or energy that imaging system 110 is capable ofacquiring.

Computing system 130 may be any suitable article, processor, chip,controller or suitable computing device suitable for processing imagesas described herein as well as controlling, coordinating or otherwisemanage components in device 100. For example, computing system 130 mayperform one or more of: causing imaging system 110 to acquire an image,process the image, cause such image to be stored on a local storage (notshown) in device 100, cause such image to be communicated to a remotedevice, e.g., by controlling transmitter/receiver 140 and the like. Insome embodiments, computing system 130 need not be a separate component;for example, parts of computing system 130 may be integral to, orembedded in, imaging system 110 or receiver transmitter 140. It will beunderstood that any functionality of computing system 130 may bedistributed to any applicable or suitable component of device 100.

Transmitter/receiver 140 may transmit and/or receive images and/or other(e.g., non-image) information to/from a remote device. For example, acomputer configured to wirelessly communicate with device 100 may beplaced near a patient and may wirelessly communicate with device 100.Transmitter/receiver 140 may be an ultra-low power radio frequency (RF)transmitter with high bandwidth input, possibly provided in chip scalepackaging, may be combined with a processing chip or circuit and maytransmit and/or receive information via an antenna as shown. Device 100may include a power source 150, such as one or more batteries. Forexample, power source 150 may include silver oxide batteries, lithiumbatteries, or other electrochemical cells having a high energy density,or the like. Other power sources may be used. Other components, modulesor units may be used. For example, power source 150 may be capable ofreceiving power from an external power source transmitting power to thedevice 100.

Embodiments of device 100 may typically be autonomous and/orself-contained. For example, the device may be a capsule or other unitwhere components are substantially contained within a container orshell, and where the device does not require any wires or cables to, forexample, receive power, obtain, store or transmit information etc.Device 100 may communicate with an external computing or communicationsystem that may receive, process, store, communicate and display imagesor other data or information received from device 100. Such remotesystem or device may further be used to control or otherwise interactwith device 100. Accordingly, it will be understood that processing ofdigital images and determining parameters related to distance and/orsize as described herein may be performed by a remote computing systemconfigured to receive images acquired by in-vivo device 100.

In some embodiments, some or all of the processing of images asdescribed herein may be performed by device 100, e.g., using computingsystem 130. In other embodiments, device 100 may perform some of theprocessing described herein and another computing system, e.g., a remotesystem may perform other processing or tasks. In yet other embodiments,device 100 may only obtain images, perform limited or no processing ofsuch acquired images and send the images to a remote computing device orsystem which may perform processing, analyzing and determining ofvarious parameters based on received images, e.g., such remote systemmay display images to a physician, receive a selection from thephysician and, determining a size of an object shown in an image basedon the physician's selection.

A storage unit may be worn on the patient's body and may communicatewith device 100 to record acquired images. The storage unit maysubsequently communicate with a computer, e.g., a workstation or serverthat may receive such stored images and further process them asdescribed herein, e.g., compute and/or calculate size of objects shownin such images.

Reference is now made to FIG. 2 that shows a schematic illustration ofan in-vivo imaging system 600, according to an embodiment of the presentinvention. According to some embodiments, system 600 may include anin-vivo imaging device, for example, an in-vivo imaging device 100 asdescribed herein. As described herein, in-vivo imaging device 100 may bea swallowable in-vivo imaging device, but other types of devices orsuitable implementations may be used. According to one embodiment,in-vivo imaging device 100 may communicate with an external receivingand display system to provide display of data, control, or otherfunctions. System 600 may include an image receiver 650 includingprocessor or controller 651 and a storage unit 655. For the sake ofsimplicity, various components that may be installed or included inimage receiver 650 are not shown. For example, image receiver 650 mayinclude output and input components or devices that may be similar toinput device 635 and an output device 640 and/or an operating systemsimilar to operating system 615, memory similar to memory 624, etc. Itwill be understood that image receiver 650 may be any suitable computingdevice and may perform any operations related to estimating ordetermining a distance, size or other dimensions of an object shown inan image as described herein.

Image receiver 650, which may include an antenna or antenna array, animage receiver storage unit 655 and a data processor or controller maybe a small device that may be carried by a patient. For example, an(e.g. ambulatory) patient may wear image receiver 650 on a belt orwrist. Image receiver 650 may communicate, e.g., wirelessly, within-vivo device 100, receive, from in-vivo device 100, images and storereceived images on storage 655. Accordingly, image receiver 650 may beattached to or worn on a patient or subject and may collect imagesobtained by in-vivo imaging device 100 over a relatively long period oftime. Image receiver 650 may be configured to communicate, wirelessly orotherwise, with computing system 610 and transfer images and/or otherinformation to computing system 610. For example, images and/or otherinformation received from in-vivo imaging device 100 may be stored onstorage 655 and may be transferred from storage 655 to computing system610, e.g., using wireless communication, a universal serial bus (USB)connection or any suitable mechanism or communication method.

Computing system 610 may analyze, process or otherwise manipulate orhandle any applicable images acquired by any suitable imaging device inany applicable environment and/or of any applicable objects. Likewise,according to embodiments of the invention, computing system 610 maycompute or derive size estimations of objects or regions in anyapplicable images. In a particular embodiment, computing system 610 mayreceive images from in-vivo device 100 or image recorder 650 and mayproduce a simulated forceps to be displayed on top of the images forestimation of a size of objects in such images. In some embodiments,in-vivo imaging device 100 may perform tasks as described herein withreference to computing system 610. For example, in-vivo imaging device100 may include some components of computing system 610 as well aspossibly, additional components. Accordingly, various operations andtasks that may be performed by computing system 610 may be performed byin-vivo imaging device 100, e.g., by computing system 130 or, in otherembodiments, by image receiver 650. In some embodiments, processing ofimages performed in order to estimate a distance, size or otherdimension of an object may be distributed. For example, a first part ofthe processing may be performed by computing system 130 in in-vivodevice 100 and a second part may be performed by system 610. Forexample, an image may be modified by computing system 130 in in-vivodevice 100 according to an illumination model, e.g., values associatedwith pixels may be altered based on an illumination or optical modelwhich may be device specific. Such pre-processed image may then becommunicated to system 610 that may perform a distance, size or otherdimension estimation.

Computing system 610 may include a processor or controller 605 that maybe, for example, a central processing unit processor (CPU), a chip orany suitable computing or computational device, an operating system 615,a memory 624, a storage 630, an input device 635 and an output device640. Operating system 615 may be or may include any code segmentdesigned and/or configured to perform tasks involving coordination,scheduling, arbitration, supervising, controlling or otherwise managingoperation of computing system 610, for example, scheduling execution ofprograms loaded into memory 624. In some embodiments, operating system615 may be a commercial operating system. Memory 624 may be or mayinclude, for example, a Random Access Memory (RAM), a read only memory(ROM), a Dynamic RAM (DRAM), a Synchronous DRAM (SD-RAM), a double datarate (DDR) memory chip, a Flash memory, a volatile memory, anon-volatile memory, a cache memory, a buffer, a short term memory unit,a long term memory unit, or other suitable memory units or storageunits. Memory 624 may be or may include a plurality of, possiblydifferent memory units.

Executable code 625 may be any executable code, e.g., an application, aprogram, a process, task or script. Executable code 625 may be executedby controller 605 possibly under control of operating system 615. Forexample, executable code 625 may be an application designed to analyzean image, to determine the distance of objects in such image from theimaging device used for acquiring the image and to create and display avirtual tool for size estimation of in-vivo objects according toembodiments of the present invention. Controller 605 may be configuredto carry out methods according to embodiments discussed herein. Storage630 may be or may include, for example, a hard disk drive, a floppy diskdrive, a Compact Disk (CD) drive, a CD-Recordable (CD-R) drive, auniversal serial bus (USB) device or other suitable removable and/orfixed storage unit.

Input devices 635 may be or may include a mouse, a keyboard, a touchscreen or pad or any suitable input device. In some embodiments, inputdevices 635 may be an input port. For example, an input port (e.g., anetwork interface card (NIC), a USB port or a wireless port or card) maybe used to receive images from image recorder 650, in-vivo device 100,or an external storage. It will be recognized that any suitable numberof input devices may be operatively connected to computing system 610 asshown by block 635. Output devices 640 may include one or more displays,speakers and/or any other suitable output devices. It will be recognizedthat any suitable number of output devices may be operatively connectedto computing system 610 as shown by block 640. Any applicableinput/output (I/O) devices may be connected to computing system 610 asshown by blocks 635 and 640. For example, a network interface card(NIC), a printer or facsimile machine, a universal serial bus (USB)device or external hard drive may be included in input devices 635and/or output devices 640.

Computing system 610 may be operatively connected to, for example, amonitor or computer monitor 660 and a point and click device 665.According to embodiments of the invention, images obtained by in-vivodevice 100 and provided to computing system 610 may be displayed onmonitor 660, for example together with virtual simulated forceps asdescribed herein.

As shown, a depth estimation model 626, which may include, for example,a tissue model, and/or an optical model and/or an illumination model, asdescribed in detail herein below, may be loaded into memory 624 (otheror different models may be used). Depth estimation model 626 mayestimate the distance of an object from the imaging device (or from theimaging system). The estimated depth (or distance) along with thetwo-dimensional display and the optical model, may translate each pixelof the two-dimensional display to three-dimensional real worldcoordinates, e.g., to the actual location of the object inthree-dimensional space. Depth estimation model 626 may be any suitablecode or data, and may be affected by execution by, for example,processor 605 or another suitable processor. In some embodiments, depthestimation model 626 may include a tissue model, an optical model, anillumination model and/or other models. It will be understood that thetissue model, optical model and illumination model discussed herein maybe implemented by any applicable construct or module and may be combinedor broken into components as known in the art. For example, in oneembodiment, these models may be a data structure that may enable anapplication to search for or determine distance values based on a set ofimaging parameters. In other embodiments, depth estimation model 626 mayinclude parameters that may be used by an application in order toderive, determine or estimate a distance of an object depicted in apixel from the imaging device at the time of capturing the image. In oneembodiment, a depth estimation model 626 may be generated based on knownoptical and/or known illumination characteristics of an imaging device.Depth estimation model 626 may map the distances of objects in the imageto create a distance map by executable code 625 and/or depth estimationmodel 626, which may indicate, for each pixel in an image, the distanceof the imaged tissue, represented in the captured image, from theimaging device. A distance map may be calculated for a displayed imageand/or may be pre-calculated for some or all images and, for example,may be stored with the image as metadata. For example, an application(e.g., executable code 625) may extract an intensity and color from apixel in an image, may modify such values, for example based on data intissue, illumination and/or optical models in depth estimation model 626and/or may use such modified values as input to depth estimation model626 in order to estimate a distance of an object (or a portion of anobject) represented by the image pixel, from the imaging device.

According to an embodiment of the invention, a tissue model may begenerated, obtained and/or provided and used as described herein.Various aspects, traits or qualities of a tissue as related to,reflected in, or represented by a digital image of the tissue may bemeasured, determined, derived or modeled. As known in the art, a pixelin a digital image may be associated with imaging parameters, values orlevels of, e.g., hue, intensity, color, brightness, luminance,chromaticity, saturation levels of such imaging parameters or any otherrelevant data, parameters or values. Such imaging parameters as relatedto a tissue or object may be affected by various aspects. In particular,such imaging parameters may be affected by the distance of the objectfrom the imaging device used for acquiring the image. Accordingly, atissue model may associate, correlate or map one or more imagingparameters, e.g., as reflected by data associated with image pixels, toa distance of the imaged object from the imaging device at the time ofcapturing the image.

A tissue model may be designed and generated such that it may besuitable for use with any patient and/or any tissue. In otherembodiments, a model may be specifically generated or adapted to aspecific tissue, patient, patient condition or other relevant aspects.For example, it may be empirically or otherwise determined that tissuesin the colon exhibit specific attributes, behavior, response or otheraspects or traits related to light and/or imaging. Accordingly, a tissuemodel may be generated in accordance with such attributes or aspectssuch that the tissue model may be used in order to process images ofcolon tissues as described herein. For example, a model generated basedon known levels or constants of absorption or reflection of light by atissue, color and intensity of light emitted from a tissue and possibly,parameters related to a relevant system and environment, may be used todetermine or estimate a distance of a tissue segment from the imagingdevice. In some embodiments, data extracted from pixels in a digitalimage may be related to a tissue model in order to calculate a distanceand/or size of an object or region.

A tissue model may be designed to be specifically adapted or suitablefor specific cases, patients, patient condition or illness, etc. Forexample, a first model may be suitable for young children and a secondmodel may be specifically suitable or adapted for old patients. A tissuemodel may be related to a condition of a patient. For example, a firsttissue model may be used for a patient who was on a normal diet when theimages were taken, while a second model may be used for a patient whowas made to abstain from food for twenty four hours, or made to drink alarge amount of liquids prior to the images being taken. In someembodiments, a base or universal model may be modified according torelevant aspects. For example, a base or universal model may be modifiedbased on the imaging system used or aspects related to the light used,e.g., intensity or color composition of light emitted by light source120. In yet other embodiments, a tissue model may be specific to aregion or anatomical organ in a body.

For example, a tissue model may be generated for the colon orgastrointestinal (GI) tract. A tissue model may represent or exhibitattributes of real tissue as reflected in a digital image. A tissuemodel may likewise symbolize, describe, stand for, contain, or be basedon, imaging parameters of a real tissue and the medium between theimaging device and the tissue, such as, for example, the in vivo fluid.For example, an interaction of a tissue with light may be known, e.g.,spectral characteristics of a given light that is made to be reflectedfrom the tissue may be studied or determined and represented by a tissuemodel. Likewise, an amount or percentage of light reflected from atissue, or imaging parameters related to the intensity, per colorintensity, hue, luminance, chromaticity or brightness of light reflectedand/or absorbed by a tissue may be studied, determined and/or known. Forexample, by examining a series of images obtained using known relevantparameters such as any relevant parameters related to the light used,the tissue being imaged, the distance of the tissue from the imagingdevice and the optical and illumination aspects or characteristics, amodel of the tissue may be generated or constructed. In someembodiments, an image may be analyzed, various aspects may bedetermined, and a tissue model may be selected or generated dynamicallyand/or automatically.

A tissue model may include a mapping of imaging or other parameters to adistance or other relevant parameters. Accordingly, a tissue model maybe used to map, correlate or associate one or more imaging or otherparameters, values or other data in an image to a distance or a size.For example, given relevant parameters related to light reflected from atissue as described herein are known and the relevant optical andillumination aspects or characteristics are known, a color and/orintensity of a tissue segment or an object as reflected by an image maybe mapped to a distance of the tissue segment or object from the imagingsystem used for obtaining the image.

Various combinations of parameters that may be extracted from, orcomputed based on, an image may be likewise mapped. For example, a levelof absorption or reflection of only part of the light spectrum may beexamined and/or mapped as described herein. In one particularembodiment, a tissue model may analyze only red light reflected from atissue. Red light may be light detected only in a red color channel ofan imager, where each of the red, blue and green color channels detectslight in a wide range of wavelengths centered about wavelengths in thered, blue and green color ranges, respectively. In one example, the redcolor range includes light having wavelengths in a range of 600-750nanometers (nm). A tissue model may map the intensity of light reflectedfrom a tissue (e.g., the colon) and detected by the red channel (or redpixel sensors) of the imager, to a distance. For example, assuming lighttraveling is attenuated according to a reciprocal relation or functionof distance, a distance of an object may be determined by the equation:D=A+B/√R, where D is the distance of the object from the imaging deviceat the time the image was acquired, A and B are constants selected asdescribed herein and R is the intensity of red light.

In generating a tissue model, any method of mapping, associating orcorrelating one or more imaging parameters such as an intensity or colorof light to a distance may be used. For example, using an image in whichthe distance of objects from the imaging system is known, a human maymanually map colors of a known tissue to distance to generate a tissuemodel (the use of the tissue model, as discussed herein, is automated).In other embodiments, extrapolation, adaptation, image analysis or othermethods or techniques may be used in order to automatically map variousparameters in an image to a distance such that a mapping, association orcorrelation of imaging parameters to distance is realized.

An illumination model may represent any relevant illumination parametersor aspects related to an acquisition of an image. An illumination modelmay include, but is not limited to, the level or intensity ofillumination or luminance emitted (e.g., by a light source such as lightsource 120) and/or absorbed or reflected (e.g., by a medium and/ortissue). For example, an illumination model may define aspects relatedto parameters such as color intensity, hue, color saturation, luminance,chromaticity, brightness of light may be used in order to compile,generate, produce or obtain an illumination model. For example, suchparameters related to an environment in which images are acquired, e.g.,the medium through which light travels before being captured by animaging device may be used in generating an illumination model.Likewise, parameters related to an irradiation or light source, e.g.,the wavelength and/or intensity of light being emitted by a light sourcemay be known and accounted for in an illumination model. A light sourcemay be fitted with lenses, mirrors or various diffractive or other opticelements. Accordingly, an illumination model may be generated such thatany relevant effect of such lenses or elements is taken into account. Anillumination model may be based on, or in accordance with, illuminationsources, lenses and other components, their respective usage, type andattributes or any other parameters that may be pertinent to illuminatingor imaging tissues or objects.

In other embodiments, an illumination model may be based on the specificdevice or system used for acquiring the relevant image. For example, thecentral point in an image may be illuminated more brightly than pointslocated near the edge of the image. Such difference in illuminationlevel or other parameters may result from the shape or othercharacteristics of the illumination sources, their location in a device,etc. In some embodiments, an illumination model may eliminate suchdifferences, calculate calibrating parameters or otherwise take any suchoptical, illumination or other aspects into account. The calibratedparameters of the illumination model may be the same for all (or all ofa set, model or series) imaging devices or may be calibratedspecifically for each device, for example, using programmableparameters. An illumination model that describes illuminationdifferences or inhomogeneity may be defined with respect to a referencegeometry or plane. For example, the reference geometry may be a sphereat radii r1 . . . rN centered about the imaging device. In someembodiments, the optimal illumination model may vary as the distancevaries between the imaged object and the illumination source or imagingdevice. Some embodiments may use an average or most often optimalillumination model or may iteratively select and switch to the optimalillumination model for each image or image stream segment.

According to embodiments of the invention, an optical model may be usedin order to process and/or analyze an image. An optical model asreferred to herein may be or may be generated based on distortion in theimage. For example, light acquired by an imaging system may travelthrough a medium (e.g., a dome or window in in-vivo device 100) and maybend non-uniformly through the medium due to optical variations therein.An optical model may include parameters or coefficients related tomagnification distortion, radial distortion, or other types ofdistortion, for example, to account for and correct such distortion inthe images. For example, an optical model may include reflection,refraction, diffraction or other optical distortion coefficients orparameters. Lenses or mirrors used by an imaging device may causespecific distortion effects throughout all the images the devicecaptures. Additionally, distortion effects may be introduced as a resultof the design, shape and other aspects of viewing window 160, as well asthe medium through which light travels when exiting device 100. Suchaspects may be accounted for in an optical model and may, accordingly,affect a mapping of imaging parameters to a distance.

An optical model may take any such aspects into account and may be usedin order to correctly or better map imaging parameters to a distance asdescribed herein. For example, an optical model may be used in order toderive one or more constants or coefficients that may be used to adjusta base tissue model to a specific environment or circumstance. Forexample, a first optical model may be generated for a first in-vivodevice 100 having a specific imaging system, viewing window and lightsource and a second optical model may be generated for a second in-vivodevice 100 having a different imaging system, viewing window and/orlight source. Accordingly, a base tissue model may be adapted to aspecific circumstance or device based on an optical model. In othercases and as described herein, an optical model may be used to modifyimaging parameters or values, e.g., prior to using a tissue model inorder to estimate a distance as described herein. In some embodiments,calibration or configuration parameters of the imaging system and/orenvironment may be used in order to derive an optical model. Forexample, a direction of light source 120 with relation to imaging system110 or the type and number of lenses or mirrors used by imaging system110 may be observed when generating an optical model. Accordingly, anoptical model may represent any optics related aspects of the equipmentand environment relevant to an acquisition of images by an in-vivodevice and may thus be used in order to correctly map imaging parametersto a distance as described herein.

Accordingly, for example, an illumination model may dictate that a levelor percentage of red color extracted from a pixel is to be modified by acertain factor. For example, based on information related to the lightsource used by in-vivo device 100 when the relevant image was obtainedit may be necessary to perform such modification prior to estimating adistance from the imaging device, for example from the imaging system110 (shown in FIG. 1), for example in millimeters, using depthestimation model 626. In another case, based on information orparameters related to lenses or mirrors used when acquiring an image, anoptical model may dictate that an intensity of light associated with thepixel is to be reduced by a certain factor, for example of 0.98.

For example, if depth estimation model 626 was designed to provide anestimation of distance (e.g., depth) of an object from the imagingdevice based on a specific light intensity of light source 120, whenusing a different (e.g., weaker) light source, an adaptation may berequired in order to produce adequate results.

In yet another embodiment, depth estimation model 626 may be anexecutable code. For example, an optical model and/or illumination modelmay be an executable code that may be provided with input in the form ofa color and intensity and may provide output in the form of modifiedvalues of color and intensity as described herein. Likewise, depthestimation model 626 may be an executable code tissue model that mayreceive a set of imaging parameters, e.g., a color and intensity and mayreturn as output distance (e.g., depth) estimation. It will beunderstood that FIG. 2 shows an exemplary schematic illustration of anin-vivo imaging system and that other embodiments or implementations arepossible. For example, some or all of the modules of depth estimationmodel 626, such as a tissue model, optical model and/or illuminationmodel, may be implemented in hardware (e.g., by an application-specificintegrated circuit (ASIC) or a chip) or they may be implemented infirmware, e.g., in order to increase speed of operation.

A virtual measurement tool may be a graphical depiction which may bedisplayed on or overlaid over an image such as an image of tissue toallow a viewer or a processor to estimate or calculate tissue size of anobject which appears in the image. In some embodiments, the virtualmeasurement tool may be used to imitate endoscopic forceps when used bya professional to estimate sizes of in-vivo objects. In contrast to theuse of endoscopic forceps for estimation of sizes, the virtualmeasurement tool may use some objective parameters to estimate thedistance of the objects from the imaging device, such as illuminationand/or color parameters that have pre-calculated correlation withdistances of in-vivo objects. Such parameters and correlations may bestored in depth estimation model 626 and may be used for estimation ofdistances as described herein.

Virtual measurement tool creator (e.g., a virtual forceps creator) 629may also be loaded into memory 624. Virtual measurement tool creator 629may be an executable code and may, for example, be embedded in,initiated by, and/or exchange data with, executable code 625, and/or maybe an executable code function that may be called by executable code625. Controller 605 may be virtual measurement tool creator 629 in thatcontroller 605 may be configured to execute code to perform thefunctions of virtual measurement tool creator 629.

Based on the distance map created by depth estimation model 626, andbased on the relative locations of the pixels of the displayed image, athree-dimensional representation of the displayed image may be created,wherein each pixel of the displayed image may be translated tothree-dimensional real world coordinates in millimeters such as, forexample, X,Y,Z coordinates or any other suitable set of coordinates in athree-dimensional space, which may represent the real three-dimensionallocations relative to the imaging device of points on the tissuerepresented by the image pixels, at the time of capturing the image.Virtual measurement tool creator 629 may create a virtual measurementtool that may be displayed, for example, as a cursor, on-screen graphicsymbol or other display on a displayed image of a tissue. The cursor mayhave a projected two-dimensional shape, having projected dimensions orlengths extending in multiple directions around an origin point whichmay be selected or marked, for example by a user or processor, on apoint or an area of interest in the displayed image. Each of themultiple projected dimensions or lengths in the multiple directionsrepresents a constant and equal virtual absolute length from the originpoint of the tool in the three-dimensional representation of the image,e.g., all the projected dimensions or lengths in the multiple directionsof a cursor may represent the same constant pre-determined virtualabsolute length that does not change during the examination from theorigin point which may be positioned or selected on a point of interestin the displayed image.

It is generally known that objects which are located further from theimaging device appear to be smaller than objects that are located nearthe imaging device. An imaged scene typically includes a plurality ofobjects which are positioned at different distances from the imagingdevice at the time of capturing the image (e.g., in vivo tissue which isimaged may have one portion located near the imaging device, and otherportions located further from the imaging device in the same imagedscene). Therefore, although the cursor's projected dimensions or lengthsfrom the origin point in the multiple directions represent a constantand equal length from the origin point in the multiple directions, theymay have different displayed dimensions or lengths and may appearnon-equal on the displayed image. In some embodiments, the virtualabsolute length may be set by a user, for example, according to theexpected and/or estimated size of in-vivo objects to be inspected.

For example, the projected dimensions or lengths in the multipledirections may represent a length l, for example in millimeters, so thatthe maximal size of the cursor along one axis from one end of the cursorto another end of the cursor may possibly be 2l (as described in detailherein, for example with reference to FIG. 3). For example, the cursormay be designed as an asterisk having 8 arms, e.g. four couples of arms,wherein in each couple of arms, the arms point to opposite directionsalong one axis, radially from the point of interest which may be ameeting point for the arms. However, the cursor may include any othersuitable number and/or arrangement of arms, or may include any othershape with multiple pre-determined directions. In some embodiments, thecursor need not necessarily include arms, for example, the cursor may beshaped as a closed curve, defined by the different lengths or dimensionsfrom the point of interest in the different directions. Any other shapeor symbol may be used to create the cursor, and in some embodiments, theuser may select or configure the shape according to personalpreferences. The directions, for example, to which the arms point or inwhich the lengths extend may be constant or may be changeable, e.g., bya user. For example, the length l may be set by a user, for example,according to the scope of sizes of the inspected objects in the image.In one example, the length may be set to 5 millimeters.

The cursor or on-screen graphic symbol according to embodiments of thepresent invention may be placed so that the point of origin is locatedon any point of interest chosen by a user on a displayed image of invivo tissue, so that the origin point is at a selected area on theimage, for example, a selected pixel or a cluster of pixels on theimage, e.g., a pixel or area chosen by a user, for example, by a mousecursor positioning and/or clicking on the image or by another inputdevice 635 or 665.

As explained, a map of distances may be calculated for the displayedimage, so that each pixel of the image may have a distance from theimaging device, calculated by depth estimation model 626. Therefore,each pixel of the displayed image of a tissue may be translated tothree-dimensional coordinates, such as, for example, X,Y,Z coordinatesin a three-dimensional space or any other suitable set ofthree-dimensional coordinates. As explained in more detail withreference to FIG. 3, the cursor or on-screen graphic symbol may bevirtually projected (e.g., added to the image) on the imaged tissue,with the origin point at a certain three-dimensional location on theimaged tissue, according to the calculated distance of the pointrepresented by the selected pixel or area relative to the imagingdevice, and based on the relative location of the pixel or area on thedisplayed image. The projected cursor may terminate at each of multipledirections at an ending point on the imaged tissue, each having theconstant virtual length l from the origin point. That is, each endingpoint may have three dimensional coordinates according to the calculateddistance and the direction of this point from the imaging device at thetime of capturing the image, calculated by depth estimation model 626,so that the distance from the origin point to each of the ending pointsis equal to the virtual length l. When projected on the displayed image,the tool may have in each of the multiple directions a projecteddimension or length on the two dimensional displayed image, according tothe projection of the length l on the displayed image at each direction.This effect may enable a user, or a processor, to make an immediateand/or intuitive estimation of sizes and/or shapes of imaged in-vivoobjects. In some embodiments, the size l may be about 4.5 mm to matchthe size of standard medical forceps. However, the invention is notlimited in that respect.

According to some embodiments of the present invention,processor/controller 605 may receive an image of in-vivo objectsobtained by in-vivo imaging device 100 (e.g., a two-dimensional imagemade up of pixels). The image may be displayed, for example, on monitor660. Processor/controller 605 may then receive an indication from a userabout a pixel or area (e.g., a selected pixel or a cluster of pixels)representing a point of interest on the image (the point of interestcorresponding to a real world in-vivo feature) or located in an area ofinterest, for example via input device 635 or 665. Then, according toembodiments of the present invention, the illumination intensity valuesof the image may be corrected, for example, by an illumination model ofdepth estimation model 626. Depth estimation model 626 may correct theillumination intensity values by the illumination model, for example, byusing a pre-calibrated illumination map that may unify the illuminationlevel through the entire spherical field of view captured by device 100.Depth estimation model 626 may then estimate, for example by the tissuemodel, the depth of a plurality of image points, e.g. pixels, around thepoint of interest or pixel, for example pixels covering a certainpredetermined area around the selected pixel/area, by converting thecorrected illumination intensity values to depths. Based on theestimated depths, the relative locations of the pixels on the image andthe optical model describing the optics distortion of device 100, depthestimation model 626 may calculate the three-dimensional coordinates ofthe plurality of image points. Thus, for example, based on the estimateddepths, a three-dimensional representation or three-dimensionalcoordinate representation (e.g., including three-dimensional coordinatesor representing the points as three-dimensional coordinates) of theimaged tissue may be created. Then, virtual tool creator 629 may cast orproject a virtual tool of a known or predetermined size, for example,created as described with reference to FIGS. 3 and 4A-4C, onto thethree-dimensional representation of the imaged tissue, as described indetail herein (e.g., add the tool to the representation or image). Then,the virtual tool may be projected onto (e.g., displayed on) thetwo-dimensional pixelated image and created or generated as, forexample, a cursor or an on-screen graphic symbol having atwo-dimensional shape on the displayed image of a tissue. As explainedwith reference to FIGS. 3 and 4A-4C, after the positions of endingpoints of the virtual tool are determined in the three-dimensionalpresentation of the tissue, the ending points may be projected on thetwo-dimensional displayed image, to the pixels representing these pointson the tissue. Based on these projected points, a cursor or anotheron-screen graphic symbol may be created and displayed, for example, bydrawing different projected dimensions or lengths in differentdirections of the cursor or on-screen graphic symbol, the dimensions orlengths ending at the projected points.

Accordingly and as described herein, embodiments of the invention mayinclude an article such as a computer or processor readable medium, or anon-transitory computer or processor storage medium, such as, forexample, a memory, a disk drive, or a USB flash memory, encoding,including or storing instructions, e.g., computer-executableinstructions, which when executed by a processor or controller, carryout methods disclosed herein. For example, a system may include anon-transitory storage medium such as memory 620, computer-executableinstructions such as executable code 625 and a controller such ascontroller 605. Some embodiments may be provided in a computer programproduct that may include a machine-readable medium stored thereoninstructions, which may be used to program a computer, or otherprogrammable devices, to perform methods as disclosed herein.

Other embodiments of the invention may be or may include a system forestimating a distance, size or other dimension of an object imaged by anin-vivo imaging system. The system may include a workstation or anyother suitable computing device comprising a memory and a processor. Thememory may be configured to store an image captured by an in-vivoimaging system, and the processor may be configured to select at leastone pixel in the image, where the pixel is associated with the imagedobject. The memory may store a tissue model, an optical model and anillumination model. The processor may be configured to calculate, basedon a tissue model (and/or an optical model and/or an illumination model)and data associated with the pixel, a distance parameter related to adistance of the object from the in-vivo imaging system at the time ofcapturing the image, wherein the tissue model is designed to provide atleast one mapping of at least one imaging parameter to at least onedistance parameter. As known in the art, a pixel in a digital image maybe associated with imaging parameters, values or levels of, e.g., hue,intensity, color, brightness, luminance, chromaticity, saturation levelsof such imaging parameters or any other relevant data, parameters orvalues. Such imaging parameters as related to a tissue or object may beaffected by various aspects. In particular, such imaging parameters maybe affected by the distance of the object from the imaging device usedfor acquiring the image. Accordingly, a tissue model may associate,correlate or map one or more imaging parameters, e.g., as reflected bydata associated with pixels, to a distance. For example, the processorto select a pixel, calculate a distance parameter related to a distanceof the object from the in-vivo imaging system or calculate a size orother dimension of the object may be controller 651 or controller 605 orit may be included in computing system 130 or computing system 610.Based on the calculated distances, the processor may create the virtualforceps cursor or on-screen graphic symbol described herein.

In some embodiments the tasks of estimating a size, distance or otherdimensions or parameters related to an object captured or imaged by animaging system or device such as in-vivo imaging device 100, and/or thetask of creating the virtual measurement tool as described herein, maybe distributed among a number of controllers, processors or computingsystems. For example, computing system 130 and controllers 605 and 651may jointly perform any computational tasks or calculations in order toestimate a distance and/or size of an object as described herein. Asdescribed herein, computing system 130 and controllers 605 and 651 maycommunicate or exchange (e.g., over wireless or wired links) any data,parameters or information. Computing system 130 and controllers 605 and651 may collaborate efforts and computational resources in performingany relevant tasks or methods described herein.

Reference is now made to FIG. 3, which is a schematic cross-sectionalillustration of virtual tool 300 being cast or projected on across-sectional illustration of a three-dimensional presentation of animaged tissue 333, for example, as may be calculated by depth estimationmodel 626 according to embodiments of the present invention. Virtualtool 300 may include an origin point P0 and extensions of identicallength l in different directions, terminating at ending points P1 andP2. As discussed herein, the processor 605 according to embodiments ofthe present invention may calculate for each pixel in an image adistance value, for example in millimeters, of the tissue represented bythe pixel from the imaging device. Based on the distance calculation,the processor 605 may create a virtual measurement tool having multipleextensions or lengths in different directions, extensions or arms inmultiple directions and an origin point from which the extensions orlengths extend, or a meeting point from which the arms project, e.g.,radially. In some embodiments, virtual tool 300 may have a shape of acircle having a fixed radius of length l, like a circled sheet or cloth,which takes shape of the three-dimensional representation surface whenplaced on it, so that in each direction, the virtual tool has a the samelength l. In this case, multiple ending points such as P1 and P2 thatmay be determined as described herein may create a closed contour alongthe edge of the circled virtual tool. This closed contour may beprojected on the two-dimensional image and create a closed shaped cursoror on-screen graphic symbol as described herein.

Distances D0, D1 and D2 are the distances from imaging device 10 oforigin point P0 and ending points P1 and P2, respectively, when tool 300is virtually placed on the imaged tissue in the three-dimensionalrepresentation. The cursor according to embodiments of the presentinvention (such as cursor or on-screen graphic symbol 310, 310 a or 310b shown in FIGS. 4A, 4B or 4C) may be positioned on a certain area onthe displayed image, for example an area chosen by a professional oruser as an area that requires inspection. In one example, a user mayposition the cursor or the graphic symbol of the virtual measurementtool on or near an area that appears abnormal in the displayed image, oran area suspected as ill or abnormal according to other parametersand/or examination. The cursor may be moved upon a displayed image, forexample, by the system (e.g., controller 651 and/or 605 described above)after receiving movement commands from a controlling user interface suchas a mouse or keyboard or another suitable user interface and/or may beautomatically moved across the image, for example, by theprocessor/controller 651 and/or 605 described above. When a point ofinterest is chosen and/or origin point P0 is placed on the point ofinterest in the three-dimensional representation of the tissue, forexample, having the three-dimensional coordinates (X0,Y0,Z0), each ofending points P1 and P2 should be positioned on points on thethree-dimensional representation of the imaged tissue, for examplehaving the three-dimensional coordinates (X1,Y1,Z1) or (X2,Y2,Z2),respectively, at an absolute distance l from the point of interest onwhich P0 is placed, in the three-dimensional representation. E.g., eachof the ending points is positioned at a same absolute distance from thepoint of interest in the three-dimensional representation. Therefore, inorder to set or determine the positions of ending points P1 and/or P2 inthe three-dimensional representation of the imaged tissue,processor/controller 605 and/or virtual measurement tool creator 629(controlled, for example, by processor/controller 605) may evaluate orcheck the absolute distance from the origin point at (X0, Y0, Z0) tomultiple points along a certain direction, represented by theirthree-dimensional coordinates. If, for a certain point, the absolutedistance equals the pre-determined distance, the certain point may beset or determined as the position of an ending point. In case theabsolute distance from the origin point at (X0, Y0, Z0) to a certainpoint equals the predetermined length l, the point may be set ordetermined as the position of an ending point such as P1 or P2.

After the positions of ending points P1 and P2 are determined in thethree-dimensional presentation of the tissue, they may be projected onthe displayed image, to the pixels representing these points on thetissue. Accordingly, processor/controller 605 and/or virtual measurementtool creator 629 may create a cursor such as, for example cursor 310,310 a or 310 b shown in FIGS. 4A, 4B or 4C, that may have multipledimensions, lengths or arms extending in multiple directions, which arethe distances from the projections of ending points P1 and P2 on thedisplayed image to the location of P0 on the displayed image, i.e., atthe selected pixel or area representing a point of interest.

Reference is now made to FIG. 4A, which is a schematic illustration of adisplayed image 500, for example captured by an in-vivo device 100 asdescribed in detail above, and a cursor 310 displayed upon or overlaidon image 500, according to embodiments of the present invention. Forexample, in the illustration of FIG. 4A, two of multiple virtual arms oftool 310, pointing at opposing directions, may have projected dimensionor length L1 and L2, respectively, ending at the projected ending pointsP1 and P2 at distal ends of the arms, respectively. The absolutedistance of points P1 and P2 on the three-dimensional representation ofthe tissue from the origin point P0 equals the predetermined length l,as shown in FIG. 3. As described in detail above, in order to determinethe positions of ending points P1 and/or P2, processor/controller 605and/or virtual measurement tool creator 629 (controlled, for example, byprocessor/controller 605) may evaluate or check the absolute distance onthe three-dimensional representation of the tissue from the origin pointP0 to multiple points on the three-dimensional representation of thetissue along a certain direction. FIGS. 4B and 4C illustrateschematically different embodiments of the cursor according toembodiments of the present invention. For example, cursor 310 b in FIG.4B is another configuration of a cursor having multiple differentdimensions or lengths or arms in multiple different directions (e.g., indifferent directions, the length or size of the cursor may differ) asdescribed herein according to embodiments of the present invention. Forexample, in some embodiments, a cursor may include scale marks along thedimensions or lengths or arms as shown in FIG. 4C. Each of thedimensions or lengths, or lengths of the arms, can be different and/oris typically different, but need not be. Other configurations of cursorsare possible according to the various embodiments of the presentinvention and the invention is not limited to the specificconfigurations shown in the drawings.

Image 500 and virtual tools/cursors 310, 310 a or 310 b may bedisplayed, for example, on a display screen. Virtual measurement tool310, 310 a or 310 b may be displayed upon or over image 500, and mayhave multiple arms or dimensions or lengths and origin or meeting pointP0 from which the arms or lengths extend radially. As discussed herein,the multiple arms or lengths may virtually represent a constant andequal absolute length, each arm or length may take on and/or set to aprojected length according to the distance from origin point P0 to anending point of the arm or length in the three-dimensionalrepresentation, for example according to embodiments of the inventiondescribed herein. Ending points P1 and P2 may be points on the displayedtissue at which the arms end when virtual measurement tool 310, 310 a or310 b is positioned, displayed in or overlaid on a certain area ondisplayed image 500. As the virtual measurement tool moves upon oracross displayed image 500, for example by receiving movement commandsfrom a controlling user interface and/or by the processor/controllermoving the tool automatically across the image, the processor 605 or651, according to embodiments of the present invention, may dynamicallychange the projected dimensions or lengths or arms of tool 310 as shownin FIGS. 4A, 4B, and 4C, according to the projected distance of thecorresponding ending points from the origin point as described herein.In the example of tool 310 a of FIG. 4B, the area defined by the contourof tool 310 a displayed on the tissue may be a known, fixed absolutearea, for example, calculated by determining a fixed radius from theorigin point marked by a user in the three-dimensional presentation ofthe tissue. The outline, circumference, contour or border marked by tool310 a may be determined using the same method as determining the endingpoints of tool 310 described above.

In some cases, the cursor may have no dimension or length or arm in acertain direction, for example, due to inability to calculate depths ordistances in a certain area of the image, for example, due to darknessor lack of clarity of the image in this area, or in cases the cursor isplaced near the margins of the image, or in areas where the tissue isabnormal, or where it is covered by content. In some cases, if theselected point of interest is in an area of where depths or distancescannot be calculated, for example, due to darkness or lack of clarity inthis image area or portion, virtual measurement tool creator 629(controlled, for example, by processor/controller 605) may look for atleast two ending points in opposite sides of the selected point ofinterest, having a distance 2l between them, as if the three-dimensionalsurface is flat and each ending point is at a distance equal to thepredetermined length l from the selected point of interest. Thus, acursor of known size 2l is created on the two-dimensional image, forestimation of sizes of objects in the image by estimating sizes relativeto the known size 2l.

Reference is now made to FIG. 5, which is a flowchart illustrating amethod for size estimation of in-vivo objects according to embodimentsof the present invention. As indicated in block 710, the method mayinclude receiving an image of in-vivo objects, for example, obtained byin-vivo imaging device 100. The image may be displayed, for example, onmonitor 660. As indicated in block 720, the method may include receivingindication of a pixel representing a point of interest from the user viaa user input device such as, for example, input device 635 or 665 inFIG. 2, for example, a mouse manipulating a cursor or any other suitablepointing method and/or device. The point of interest may be, forexample, a point in an image corresponding to a real-world in-vivofeature. As indicated in block 730, the method may include correctingthe illumination intensity values of the image, for example, by anillumination model that may be included in the depth estimation model626. Depth estimation model 626 may correct the illumination intensityvalues by the illumination model, for example, by using a pre-calibratedillumination map that may unify the illumination level through theentire spherical field of view captured by device 100. As indicated inblock 740, the method may include estimating by the tissue model thedepth of a plurality of image points, e.g., pixels, around, near orimmediately surrounding the point of interest, by converting thecorrected illumination intensity values to depths. As indicated in block750, the method may include calculating the three-dimensionalcoordinates' representation of the plurality of image points, based onthe estimated depths, the relative locations of the pixels on the imageand the optical model describing the optics distortion of device 100.Thus, for example, a three-dimensional representation of the imagedtissue may be created. As indicated in block 760, the method may includeprojecting or casting (e.g., adding to) a virtual tool of a known sizeonto the three-dimensional representation of the imaged tissue. Asindicated in block 770, the method may include adding or projecting thevirtual tool onto the two-dimensional pixelated image and drawn as, forexample, a cursor or another on-screen graphic symbol having atwo-dimensional shape on the displayed image of a tissue, so that theresulting cursor or on-screen graphic symbol is displayed to the user ontop of the displayed image. The virtual tool and pixelated image may bedisplayed on, e.g., monitor 660, or another display device.

According to some embodiments of the present invention, projecting orcasting a virtual tool of a known size onto the three-dimensionalrepresentation of the imaged tissue may include creating a virtualmeasurement tool having multiple extensions or lengths or arms inmultiple directions and an origin point from which the extensions orlengths or arms extend, for example, as shown in FIGS. 3, 4A, 4B and/or4C. The cursor according to embodiments of the present invention may bepositioned on a certain area on the displayed image, for example, anarea chosen by a professional or user as an area that requiresinspection. In one example, a user may position the cursor or thegraphic symbol of the virtual measurement tool on or near an area thatappears abnormal in the displayed image, or an area suspected as ill orabnormal according to other parameters and/or examination.

Projecting or casting a virtual tool may further include positioningending points of the tool's outline, border, contour, extensions orlengths on points defined by three coordinates in three-dimensionalspace, on the three-dimensional representation of the imaged tissue,wherein each of the ending points is positioned at an absolute distancel from the point of interest in the three-dimensional representation.The positioning may be performed, for example, by evaluating or checkingthe absolute distance from the origin point to multiple points on thethree-dimensional representation of the tissue along a certaindirection. In case for a certain point the absolute distance equals thepredetermined length l, the point may be set or determined as theposition of an ending point.

Projecting of the virtual tool onto or adding it to the two-dimensionalpixelated image may include creating a cursor such as, for example,cursors 310, 310 a or 310 b shown in FIGS. 4A, 4B or 4C, respectively,that may have multiple projected dimensions or lengths in multipledirections, which are the distances on the two-dimensional image fromthe ending points, projected on the displayed image, to the point ofinterest, selected or marked on the displayed image, e.g., at theselected pixel or area representing the point of interest.

According to some embodiment of the invention, the projected virtualmeasurement tool, e.g., cursor, may be displayed upon a displayed image.The projected measurement tool may be moved over the displayed image,for example, by a user inputting movement commands, for example, by amouse or keyboard or another suitable input device. In otherembodiments, the virtual tool may be moved over the image automaticallyby the processor. The projected dimensions or lengths of the tool may bechanged dynamically according to the distances on the two-dimensionalimage from the ending points, projected on the displayed image, to thepoint of interest, projected on the displayed image, wherein the pointof interest is changed as the cursor moves over the displayed image.

It will be appreciated that the maximal size of the virtual tool, e.g.,the absolute equal size of the tools' extensions or lengths, may be setby a user according to, for example, a typical and/or expected size ofobjects being examined or needs to be examined.

It may be appreciated that an image or frame may be a digital or analogrepresentation of real-life objects and that reference to objects in theframe may refer to the visual representation of those objects. Forexample, the size of objects in an image may refer to a region of pixelsin the image that visually represent a real-life object.

It is noted that while embodiments of the invention described herein areadapted for imaging of the GI tract, the devices and methods disclosedherein may be adapted for imaging other body cavities or spaces.

Different embodiments are disclosed herein. Features of certainembodiments may be combined with features of other embodiments; thuscertain embodiments may be combinations of features of multipleembodiments.

The foregoing description of the embodiments of the invention has beenpresented for the purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed. It should be appreciated by persons skilled in the art thatmany modifications, variations, substitutions, changes, and equivalentsare possible in light of the above teaching. It is, therefore, to beunderstood that the appended claims are intended to cover all suchmodifications and changes as fall within the true spirit of theinvention.

What is claimed is:
 1. A method for size estimation of in-vivo objects,the method comprising: displaying a two-dimensional image of in-vivoobjects obtained by an in-vivo imaging device, said image comprisingimage pixels; receiving indication of a selected area representing apoint of interest from the user; estimating the depth of a plurality ofimage pixels around the selected area; calculating a three-dimensionalcoordinate representation of the plurality of image pixels, based on theestimated depths; casting a virtual tool of a known size onto thethree-dimensional representation to determine ending points of the tool;and projecting the virtual tool onto the two-dimensional image to createa cursor having a two-dimensional shape on the displayed image, thecursor having multiple dimensions in different directions, thedimensions end at the determined ending points projected on thetwo-dimensional image.
 2. The method according to claim 1, wherein saidcasting of a virtual tool of a known size onto the three-dimensionalrepresentation of the imaged tissue comprises: creating a virtual toolhaving an origin point and multiple lengths from the origin point inmultiple directions that end at said ending points in the multipledirections; and positioning said ending points of the multiple lengthson points defined by three coordinates in three-dimensional space, onthe three-dimensional representation, wherein each of the ending pointsis positioned at a same absolute distance from the point of interest inthe three-dimensional representation.
 3. The method according to claim2, wherein said positioning comprises: checking the absolute distancefrom the origin point to multiple points on the three-dimensionalrepresentation of the tissue along a certain direction; and if, for acertain point, the absolute distance equals the pre-determined distance,determining the certain point as the position of an ending point.
 4. Themethod according to claim 2, wherein said projecting comprises creatinga two-dimensional cursor having multiple projected dimensions inmultiple directions, the projected dimensions are the distances on thetwo-dimensional image from the ending points, projected on the displayedimage, to the point of interest, selected on the displayed image.
 5. Themethod according to claim 4, wherein the cursor is movable over thedisplayed image, while the projected dimensions are changeabledynamically according to the distances on the two-dimensional image fromthe ending points, projected on the displayed image, to the point ofinterest, selected on the displayed image, wherein the point of interestis changed as the cursor moves over the displayed image.
 6. The methodaccording to claim 1, wherein the image is displayed on a computermonitor.
 7. A system for size estimation of in-vivo objects, the systemcomprising: a workstation comprising a memory and a processor, thememory to store an image captured by an in-vivo imaging device, and theprocessor to: display a two-dimensional image of in-vivo objectsobtained by in-vivo imaging device; receive indication of a selectedarea representing a point of interest from the user via a user inputdevice; estimate depth of a plurality of image pixels around theselected area; calculate three-dimensional coordinates representation ofthe plurality of image pixels, based on the estimated depths; cast avirtual tool of a known size onto the three-dimensional representationto determine ending points of the tool; and project the virtual toolonto the two-dimensional image to create a cursor having atwo-dimensional shape on the displayed image, the cursor having multipledimensions in different directions, the dimensions end at the determinedending points projected on the two-dimensional image.
 8. The systemaccording to claim 7, wherein said processor is to: create a virtualtool having an origin point and multiple lengths from the origin pointin multiple directions that end at said ending points in the multipledirections; and position said ending points of the multiple lengths onpoints defined by three coordinates in three-dimensional space, on thethree-dimensional representation, wherein each of the ending points ispositioned at a same pre-determined absolute distance from the point ofinterest in the three-dimensional representation.
 9. The systemaccording to claim 8, wherein said processor is to: check the absolutedistance from the origin point to multiple points on thethree-dimensional representation of the tissue along a certaindirection; and if, for a certain point, the absolute distance equals thepre-determined distance, determine the certain point as the position ofan ending point.
 10. The system according to claim 8, wherein saidprocessor is to create a two-dimensional cursor having multipleprojected dimensions in multiple directions, the projected dimensionsare the distances on the two-dimensional image from the ending points,projected on the displayed image, to the point of interest, selected onthe displayed image.
 11. The system according to claim 7, wherein thecursor is movable over the displayed image, while the projecteddimensions are changeable dynamically according to the distances on thetwo-dimensional image from the ending points, projected on the displayedimage, to the point of interest, selected on the displayed image,wherein the point of interest is changed as the cursor moves over thedisplayed image.
 12. The system according to claim 8, wherein thetwo-dimensional image and cursor are displayed on a computer monitor.13. A method for size estimation of in-vivo objects, the methodcomprising: creating a virtual measurement tool for size estimation ofin-vivo objects, the tool comprising: an origin point on a point ofinterest on a displayed two-dimensional image; and multiple lengths fromthe origin point in multiple directions in a three-dimensionalrepresentation of the image of a tissue captured by said in-vivo imagingdevice, each length having an ending point at a distal end of thelength, positioned on a point in the three-dimensional representation ofthe image, wherein the ending points have the same absolute distancefrom the origin point in the three-dimensional representation, andprojecting the virtual measurement tool on said image, for creating atwo-dimensional cursor having multiple projected dimensions in multipledirections, the projected dimensions being the distances on thetwo-dimensional image from the ending points, projected on the displayedimage, to the point of interest, selected on the displayed image. 14.The method according to claim 13, comprising creating saidthree-dimensional representation of said image, by: estimating depth ofa plurality of image pixels around a selected area representing a pointof interest; and calculating three-dimensional coordinatesrepresentation of the plurality of image points, based on the estimateddepths.
 15. The method according to claim 13, wherein said creating avirtual tool comprises positioning ending points of the multiple lengthson points defined by three coordinates in three-dimensional space, onthe three-dimensional representation, wherein each of the ending pointsis positioned at a same pre-determined absolute distance from the pointof interest in the three-dimensional representation.
 16. The methodaccording to claim 14, wherein said positioning comprises: checking theabsolute distance from the origin point to multiple points on thethree-dimensional representation of the tissue along a certaindirection; and if, for a certain point, the absolute distance equals thepre-determined distance, determining the certain point as the positionof an ending point.
 17. The method according to claim 13, wherein theimage is captured by an in-vivo device.
 18. The method according toclaim 13, wherein the image and cursor are displayed on a computermonitor.